told CNBC’s "Squawk Box."A woman adjusts her face mask at Barons Court Underground station in London on November 29, 2021. - Britain will require all arriving passengers to isolate until they can show a negative PCR test against Covid-19 and is restoring a mandate to wear fa Bancel emphasized that while a new vaccine could take "60 to 90 days" to be approved by regulators, "the question is...